Safe and efficient transfer of natural gas (NG) requires that the natural gas be liquefied prior to shipment. Once the liquefied natural gas (LNG) arrives at the target location, the natural gas must be regasified before it can be used as a fuel source. The regasification or vaporization of the liquefied natural gas, which requires input of work or heat, provides an opportunity for secondary power generation that uses the initially cold temperatures of the liquefied natural gas and the work or heat input for vaporization.
Previous known processes for generating power in association with vaporization of liquefied natural gas, however, were less than optimal for several reasons. For example, processes where the working fluid was only partially condensed were known to cause complexities, including the need for phase separators, which in turn increased costs and perhaps more importantly, rendered the processes more difficult to control and more sensitive to upsets that might unduly stress heat exchange equipment. Moreover, some processes suffered from thermodynamic inefficiencies due to mixing losses when the streams with different compositions were combined. Finally, the known processes did not disclose use of natural gas as a component of the working fluid.